Cut the fish fillets into 1-inch thick strips and place them in a shallow dish. In a small bowl, combine lime juice, olive oil, chili powder, cumin, garlic powder, salt, and black pepper to create the marinade.

Pour the marinade over the fish, ensuring all pieces are well coated. Let the fish marinate for at least 15 minutes at room temperature, or refrigerate for up to 30 minutes if preparing ahead.

Preheat your grill or grill pan to medium-high heat. Lightly oil the grill grates to prevent the fish from sticking.

Place the marinated fish strips on the hot grill. Cook for 2-3 minutes per side, or until the fish is opaque and easily flakes with a fork.

While the fish is grilling, warm the corn tortillas. You can do this on the grill for 15-30 seconds per side, in a dry skillet, or wrapped in a damp paper towel and microwaved.

To assemble, place a portion of grilled fish in the center of each warm tortilla. Top with shredded cabbage, sliced avocado, salsa, a dollop of sour cream or Greek yogurt, and a sprinkle of fresh cilantro.

Serve immediately with lime wedges on the side for an extra burst of freshness.